Lumbar Zygapophysial (Facet) Joint Radiofrequency Denervation Success as a Function of Pain Relief During Diagnostic Medial Branch Blocks: A Multicenter Analysis

Spine J. May-Jun 2008;8(3):498-504. doi: 10.1016/j.spinee.2007.04.022. Epub 2007 Jun 18.

Abstract

Background context: The publication of several recent studies showing minimal benefit for radiofrequency (RF) lumbar zygapophysial (l-z) joint denervation have led many investigators to reevaluate selection criteria. One controversial explanation for these findings is that the most commonly used cutoff value for selecting patients for l-z (facet) joint RF denervation, greater than 50% pain relief after diagnostic blocks, is too low and hence responsible for the high failure rate.

Purpose: To compare l-z joint RF denervation success rates between the conventional greater than or equal to 50% pain relief threshold and the more stringently proposed greater than or equal to 80% cutoff for diagnostic medial branch blocks (MBB).

Study design/setting: Multicenter, retrospective clinical data analysis.

Patient sample: Two hundred and sixty-two patients with chronic low back pain who underwent l-z RF denervation at three pain clinics.

Outcome measures: Outcome measures were greater than 50% pain relief based on visual analog scale or numerical pain rating score after RF denervation persisting at least 6 months postprocedure, and global perceived effect (GPE), which considered pain relief, satisfaction and functional improvement.

Methods: Data were garnered at three centers on 262 patients who underwent l-z RF denervation after obtaining greater than or equal to 50% pain relief after diagnostic MBB. Subjects were separated into those who received partial (greater than or equal to 50% but less than 80%) and near-complete (greater than or equal to 80%) pain relief from the MBB. Outcomes between groups were compared with multivariate analysis after controlling for 14 demographic and clinical variables.

Results: One hundred and forty-five patients obtained greater than or equal to 50% but less than 80% pain relief after diagnostic MBB, and 117 patients obtained greater than or equal to 80% relief. In the greater than or equal to 50% group, success rates were 52% and 67% based on pain relief and GPE, respectively. Among patients who experienced greater than 80% relief from diagnostic blocks, 56% obtained greater than or equal to 50% relief from RF denervation and 66% had a positive GPE.

Conclusions: Using more stringent pain relief criteria when selecting patients for l-z joint RF denervation is unlikely to improve success rates, and may lead to misdiagnosis and withholding a potentially valuable treatment from good candidates.

Publication types

  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Anesthetics, Local / therapeutic use
  • Denervation / methods
  • Female
  • Humans
  • Low Back Pain / drug therapy
  • Low Back Pain / radiotherapy*
  • Lumbar Vertebrae
  • Male
  • Middle Aged
  • Nerve Block
  • Patient Selection*
  • Zygapophyseal Joint / innervation
  • Zygapophyseal Joint / radiation effects*

Substances

  • Anesthetics, Local